The present disclosure relates generally to fuel cell systems, and particularly to thermal management of fuel cell systems.
Fuel cell systems may employ electrolysis modules in combination with fuel cell modules, thereby providing a regenerative fuel cell system. A typical fuel cell module receives hydrogen fuel, from either the electrolysis module or through an intermediate hydrogen storage device, and oxygen to generate electricity and product water, while a typical electrolysis module receives process water from a water storage device and electricity to produce hydrogen, oxygen, and byproduct water. Another byproduct of both the electrolysis and fuel cell modules is heat, which is typically distributed throughout the fuel cell system via the product and process water. With the presence of water, it is preferable to operate the fuel cell system at a temperature above the freezing temperature of water, typically zero degree Celsius but with some variation depending on pressure. However, in cold climates or at high altitudes, such cold temperatures are unavoidable. With high altitude airships (HAA), for example, the ambient temperature may reach as low as −55 degree-Celsius or below. In such environments, auxiliary heating systems, such as electric heaters, may be used to prevent water freezing. However, such auxiliary systems have high energy demands. Accordingly, it would be advantageous to have an intelligent fuel cell system that can utilize available thermal energy to maintain operating temperatures above the freezing temperature of water.